LISTBOX Get property

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4D v20 R7


LISTBOX Get property ( {* ;} object ; property ) -> Function result

Parameter	Type	Description
*	Operator	If specified, object is an object name (string). If omitted, object is a variable
object	Form object	Object name (if * is specified) or Variable (if * is omitted)
property	Longint	Property whose value you want to get
Function result	Longint, String	Current value

Description

The LISTBOX Get property command returns the value of the property of the list box or column specified using the object and * parameters.

If you pass the optional * parameter, you indicate that the object parameter is an object name (string). If you do not pass this parameter, you indicate that the object parameter is a variable. In this case, you pass a variable reference instead of a string. For more information about object names, refer to the Object Properties section.

Note: If the list box or column specified using the object and * parameters does not exist, the LISTBOX Get property command returns -1 for numeric properties, or an empty string.

In the property parameter, pass a constant indicating the property whose value you want to get. You can use one of the following constants from the “List Box” theme:

Constant	Value	Comment
lk allow wordwrap	14	Wordwrap property Applies to: Column* Possible values: lk no (0) lk yes (1)
lk auto row height	31	Automatic row height property for array type list box Applies to: List box or column Possible values: lk no (0) lk yes (1)
lk background color expression	22	Background Color Expression property for record selection, collection or entity selection type list boxes Applies to: List box or column
lk cell horizontal padding	36	Cell horizontal padding in pixels (same value for left and right padding) Applies to: List box, column, header, footer
lk cell vertical padding	37	Cell vertical padding in pixels (same value for top and bottom padding) Applies to: List box, column, header, footer
lk column max width	26	Maximum Width property Applies to: Column*
lk column min width	25	Minimum Width property Applies to: Column*
lk column resizable	15	Resizable property Applies to: Column* Possible values: lk no (0) lk yes (1)
lk detail form name	19	Detail Form Name property for selection type list box Applies to: List box
lk display footer	8	Display Footers property Applies to: List box Possible values: lk no (0): hidden lk yes (1): shown
lk display header	0	Display Headers property Applies to: List box Possible values: lk no (0): hidden lk yes (1): shown
lk display type	21	Display Type property for numeric columns Applies to: Column* Possible values: lk numeric format (0): displays values in numeric format lk three states checkbox (1): displays values as three-state checkboxes
lk double click on row	18	Double-click on row property for selection type list box Applies to: List box Possible values: lk do nothing (0): does not trigger any automatic action lk edit record (1): displays corresponding record in read-write mode lk display record (2): displays corresponding record in read-only mode
lk extra rows	13	Hide extra blank rows property Applies to: List box Possible values: lk display (0) lk hide (1)
lk font color expression	23	Font Color Expression property for record selection, collection or entity selection type list boxes Applies to: List box or column
lk font style expression	24	Style Expression property for record selection, collection or entity selection type list boxes Applies to: List box or column
lk hide selection highlight	16	Hide selection highlight property Applies to: List box Possible values: lk no (0) lk yes (1)
lk highlight set	27	Highlight Set property for selection type list box Applies to: List box
lk hor scrollbar height	3	Height in pixels
lk movable rows	35	Movable Rows property for array type list box Applies to: List box (excluding hierarchical mode) Possible values: lk no (0): Rows cannot be moved at runtime lk yes (1): Rows can be moved at runtime (default)
lk multi style	30	Multi-style property Applies to: Column* Possible values: lk no (0) lk yes (1)
lk named selection	28	Named Selection property for selection type list box Applies to: List box
lk resizing mode	11	Column Auto-Resizing property Applies to: List box Possible values: lk manual (0) lk automatic (2)
lk row height unit	17	Unit of Row Height property Applies to: List box Possible values: lk lines (1) lk pixels (0)
lk selection mode	10	Selection Mode property Applies to: List box Possible values: lk none (0) lk single (1) lk multiple (2)
lk single click edit	29	Single-Click Edit property Applies to: List box Possible values: lk no (0) lk yes (1)
lk sortable	20	Sortable property Applies to: List box Possible values: lk no (0) lk yes (1)
lk truncate	12	Truncate with ellipsis property Applies to: List box or column Possible values: lk without ellipsis (0) lk with ellipsis (1)
lk ver scrollbar width	5	Width in pixels

*These properties only apply to list box columns; if you pass a list box as parameter with one of these properties, LISTBOX Get property returns -1, or an empty string, depending on the property passed.

In general, to signal an invalid result LISTBOX Get property returns -1 when retrieving properties that have numeric values, or an empty string; however, no errors are generated. More specifically, this occurs in the following cases:

If you pass a property that does not exist
If you pass a property that is not available for the specified list box or column, e.g. you pass the lk font color expression property with an array type list box
If you pass a column as parameter with a property that is applied to a list box, and vice versa if you pass a list box as parameter with a property that is applied to a column (see * above)

In addition, it is not possible to return values from more than one column at a time; if you attempt to use the "@" symbol as part of a column name to indicate multiple columns with similar names, LISTBOX Get property returns the first matching value it finds; as a result, the value returned has no true significance.

Notes:

The lk display footer and lk display header constants are useful for calculating the actual size of a list box area in a form.
When you use the constants _o_lk hor scrollbar position or _o_lk ver scrollbar position, the LISTBOX Get property command returns the position of the scrolling cursor in relation to its original position, i.e. the size of the hidden part of the window, expressed in pixels. By default, this position corresponds to 0. Combined, for example, with information concerning the row height, this value lets you find out the contents displayed in the listbox. However, these constants are deprecated and can be favorably replaced with the OBJECT GET SCROLL POSITION command.
The statement LISTBOX Get property(vLB;_o_lk footer height) returns the same value as the LISTBOX Get footers height command when footers are displayed. However, if footers are not displayed, LISTBOX Get property returns 0 while LISTBOX Get footers height still returns the height, in this case theoretical, of the footers.

Example 1

Given a listbox "MyListbox", if you execute the following statement:

$Value:=LISTBOX Get property(*;"MyListbox";lk selection mode) // value returned indicates selection mode

In this case, the result returned indicates whether multiple rows can be selected.

Example 2

Given a list box "MyListbox", if you execute the following statement:

$resizable:=LISTBOX Get property(*;"MyListbox";lk column resizable)

LISTBOX Get property returns -1 because the lk column resizable property applies to columns and a list box was passed as parameter.